A tube glass product used in, for example, a medical ampule and a fluorescent tube for lighting is formed by various methods such as a Danner method and a down-draw method. The overview of the Danner method is described below as an example.
When a tube glass product is manufactured by the Danner method, a molten glass is first supplied to a rotatable sleeve arranged in a muffle furnace. The supplied molten glass is formed into a tube shape while being wound on an inside of the sleeve. Then, the molten glass formed into a tube shape is pulled out from a distal end of the sleeve with a tube drawing device (pulling device) to form a tube glass continuously. After that, the formed tube glass (continuous tube glass) is cut to a predetermined length with a cutting device to obtain a tube glass product having a predetermined length (see, for example, Patent Literature 1).
Further, in this case, as a method of cutting the continuous tube glass, there has been generally adopted a method involving bringing a cutting blade into contact with an outer peripheral surface of the continuous tube glass that is conveyed continuously to form scratches on the outer peripheral surface, and applying thermal shock to the scratches, to thereby cut the continuous tube glass (see, for example, Patent Literature 2).